1. Field of the Invention
The present invention relates to a method for producing aglycone in which sugar residues are removed from a glycoside, particularly a method for producing aglycone from a glycoside efficiently at low cost without using an acid catalyst and an organic solvent.
2. Related Art
Many physiological active substances often have a structure in which naturally, sugar residues are bound to a matrix compound (hereinafter referred to as aglycone) composed of nonsugar moiety. It is said that presence of the sugar residues is purposed for stabilization, hydrophilicity, and detoxification. Therefore, physiological activities such as medical effect, antioxidance, and anticancer effect of the glycoside ordinarily exist in an aglycone region.
When orally administered, sugar residues of generally water-soluble glycoside are removed by intestinal bacteria and digestive enzymes, converting into aglycone which is easily absorbed into the intestinal tract. If aglycone is administered from the beginning, the increases in the intestinal absorption rate and the concentration in blood are expected.
As a method for extracting aglycone from a natural glycoside, conventionally-known methods are an enzyme reaction using glycosidase (Patent Documents 1 and 2) and an acid hydrolysis method (Patent Document 3). Further, Patent Document 4 describes a method that the aglycone freed by the above-described enzyme reaction and acid hydrolysis method is extracted into liquid in a subcritical state or supercritical state.    Patent Document 1: Japanese Unexamined Patent Publication No. 2006-081440    Patent Document 2: Japanese Unexamined Patent Publication No. 2005-224162    Patent Document 3: Japanese Unexamined Patent Publication No. H09-104693    Patent Document 4: Japanese Unexamined Patent Publication No. S63-33341